Optical modules, which are one of the main component of projectors (projection type display apparatus), typically include an illumination optical system (illumination device) including a light source, and an optical system for projection (projection optical system) including a light modulation device. In recent years, small-size (palm-size) and lightweight portable projectors which are called micro projector are becoming widely used in the area of the projector. In the past, in the micro projector, LED (Light Emitting Diode) has been mainly used as a light source of an illumination device.
On the other hand, nowadays, a laser is drawing attention as a new light source of the illumination device. For example, as a projector using laser light of three primary colors of red (R), green (G), and blue (B), a projector using a gas laser has been known. The projector using a laser as a light source is proposed in, for example, Patent Documents 1 and 2. When a laser is adopted as a light source, a projector which provides a wide range of color reproduction and small power consumption can be obtained.